Instruction Manual
D200126X012
Fisher™ 2502 Controllers
2502 Controllers
June 2017
Contents
Introduction 2.................................
Scope of Manual 2.............................
Description 2.................................
Specifications 2...............................
Educational Services 2.........................
Installation 4..................................
249 Sensors 5................................
Uncrating 5..................................
Controller Orientation 6........................
Controller‐Sensor Action 6......................
Mounting Caged Sensors 7.....................
Mounting Cageless Sensors 9...................
Side‐Mounted Sensor 9.....................
Top‐Mounted Sensor 10....................
Supply Pressure 11............................
Prestartup Checks 12...........................
Adjustments 13...............................
Level Set Adjustment 13....................
Proportional Band Adjustment 13............
Reset Adjustment 14.......................
Differential Relief Adjustment 15.............
Calibration 15..................................
Precalibration Requirements 15.................
Wet Calibration 15.........................
Dry Calibration 15.........................
Controller and Torque Tube Arm
Disassembly 16.........................
Determining Suspended Weight
for Calibration 16........................
Calibration Procedure 17.......................
Startup 18.....................................
Principle of Operation 19........................
2502 Controller 21............................
2502F Controller with Reset
Relief Valve 21..............................
Maintenance 22................................
Troubleshooting 23............................
Removing Controller from Sensor 24.............
Figure 1. Fisher 2502 Controller Mounted on 249B
Sensor
2502 CONTROLLER
249B SENSOR
W8334
Changing Mounting Method 25.................
Installing Controller on Sensor 26................
Changing Proportional, Reset, or
Differential Relief Valve 27..................
Testing Relay Dead Band 27.....................
Changing Relay 27.............................
Replacing Bellows 27..........................
Reversing Action 28...........................
Parts Ordering 29...............................
Parts Kits 29...................................
Parts List 29...................................
www.Fisher.com
2502 Controllers
June 2017
Instruction Manual
D200126X012
Introduction
Scope of Manual
This instruction manual provides installation, operating, calibration, and maintenance procedures for Fisher 2502
pneumatic controllers (figure 1) used in combination with Fisher 249 level sensors.
This manual does not include regulator or sensor installation or maintenance procedures. For this information, refer to
the instruction manual for the appropriate regulator and 249 level sensor.
Do not install, operate, or maintain a 2502 controller without being fully trained and qualified in valve, actuator, and
accessory installation, operation, and maintenance. To avoid personal injury or property damage, it is important to
carefully read, understand, and follow all contents of this quick start guide, including all safety cautions and warnings.
If you have any questions about these instructions, contact your Emerson sales office
proceeding.
or Local Business Partner before
Description
The 2502 controller described in this manual provides proportional‐plus‐reset and proportional‐plus‐reset with
differential relief valve control. The controller output is a pneumatic signal that operates a final control element. These
controllers are designed to control liquid level, the level of interface between two liquids, or density (specific gravity).
Each unit consists of a 249 liquid level sensor and a 2502 pneumatic controller.
Refer to the Principle of Operation section for a more comprehensive discussion of how the 2502 pneumatic controller
operates.
Specifications
Table 1 gives general specifications for 2502 controllers.
Educational Services
For information on available courses for the 2502 controller, as well as a variety of other products, contact:
Emerson Automation Solutions
Educational Services - Registration
Phone: 1-641-754-3771 or 1-800-338-8158
E-mail: education@emerson.com
emerson.com/fishervalvetraining
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Instruction Manual
D200126X012
Table 1. Specifications
2502 Controllers
June 2017
Available Configurations
2502: A direct‐acting controller which provides
proportional‐plus‐reset control
2502C: A 2502 with a level indicator assembly
2502F: A 2502 with a differential relief valve
These products are also available with reverse action.
For example, 2502R, 2502CR, and 2502FR
Input Signal
Liquid Level or Liquid‐to‐Liquid Interface Level: From
0 to 100 percent of displacer length—standard
lengths for all sensors are 356 mm (14 inches) or 813
mm (32 inches). Other lengths available depending
on sensor construction
Liquid Density: From 0 to 100 percent of
displacement force change obtained with given
displacer volume—standard volumes are 980 cm
3
inches
) for 249C and 249CP sensors, or 1640 cm
3
(100 inches3) for most other 249 sensors; other
volumes available depending on construction
Output Signal
0.2 to 1.0 bar (3 to 15 psig) or 0.4 to 2.0 bar
(6 to 30 psig)
Action: Field reversible between direct (increasing
liquid or interface level or specific gravity increases
output pressure) and reverse (increasing liquid or
interface level or specific gravity decreases output
pressure)
Area Ratio of Relay Diaphragms
3:1
Supply Medium
Air or Natural Gas
Supply medium must be clean, dry, and noncorrosive
Per ISA Standard 7.0.01
A maximum 40 micrometer particle size in the air
system is acceptable. Further filtration down to 5
micrometer particle size is recommended. Lubricant
content is not to exceed 1 ppm weight (w/w) or
volume (v/v) basis. Condensation in the air supply
should be minimized
Per ISO 8573-1
Maximum particle density size: Class 7
Oil content: Class 3
Pressure Dew Point: Class 3 or at least 10_C less than
the lowest ambient temperature expected
(60
3
(continued)
Supply Pressure Requirement
(1)
1.4 bar
output signal or 2.4 bar
(20 psig) for 0.2 to 1.0 bar (3 to 15 psig)
(1)
(35 psig) for 0.4 to 2.0 bar
(6 to 30 psig) output signal
Maximum Supply Pressure
(2)
3.4 bar (50 psig)
Supply Pressure Consumption
(3)
At 1.4 bar (20 Psig)
3
Minimum: 0.11 normal m
band setting of 0 or 200 percent
Maximum: 0.72 normal m
/h (4.2 scfh) at proportional
3
/h (27 scfh) at proportional
band setting of 100 percent
At 2.4 bar (35 psig)
Minimum: 0.2 normal m
3
/h (7 scfh) at proportional
band setting of 0 or 200 percent
Maximum: 1.1 normal m
3
/h (42 scfh) at proportional
band setting of 100 percent
Performance
Hysteresis: 0.6 percent of output pressure change at
100 percent of proportional band
Repeatability: 0.2 percent of displacer length or
displacement force change
Dead Band: 0.05 percent of proportional band or
span
Typical Frequency Response: 4 Hz and 90‐degree
phase shift at 100 percent of proportional band with
output piped to typical instrument bellows using 6.1
meters (20 feet) of 6.4 mm (1/4 inch) tubing
Ambient Temperature Error: $1.5 percent of output
pressure change per 50_F (28_C) of temperature
change at 100 percent of proportional band when
using sensor with standard‐wall N05500 torque tube
with 249 sensors
Reset: Adjustable from 0.01 to 74 minutes per repeat
(100 to 0.01 repeats per minute)
Differential Relief (2502F and 2502FR Controllers
Only): Adjustable from 0.1 to 0.48 bar differential (2
to 7 psi) to relieve excessive difference between
proportional and reset pressures. Differential relief
can be switched between rising output pressure and
falling output pressure.
Standard Tubing Connections
1/4 NPT internal
Maximum Working Pressures (Sensors Only)
Consistent with applicable ASME
pressure/temperature ratings
3
2502 Controllers
June 2017
Table 1. Specifications (continued)
Instruction Manual
D200126X012
Hazardous Area Classification
2502 controllers comply with the requirements of
ATEX Group II Category 2 Gas and Dust
Declaration of SEP
Fisher Controls International LLC declares this
product to be in compliance with Article 4 paragraph
3 of the PED Directive 2014/68/EU. It was designed
and manufactured in accordance with Sound
Operative Ambient Temperatures
(2)
Standard Construction: -40 to 71_C (-40 to 160_F)
High Temperature Construction: -18 to 104_C (0 to
220_F)
See figure 2
NOTE: Specialized instrument terms are defined in ANSI/ISA Standard 51.1 - Process Instrument Terminology.
1. Control and stability may be impaired if this pressure is exceeded.
2. The pressure/temperature limits in this document, and any applicable standard or code limitation should not be exceeded.
3. Normal cubic meters per hour (m
3
/hr) at 0_C and 1.01325 bar. Scfh=standard cubic feet per hour at 60_F and 14.7 psia .
Engineering Practice (SEP) and cannot bear the CE
marking related to PED compliance.
However, the product may bear the CE marking to
indicate compliance with other applicable European
Community Directives.
Figure 2. Guidelines for Use of Optional Heat Insulator Assembly
AMBIENT TEMPERATURE
_
-18 -10
110
0
800
10 20
(_C)
0
HEAT INSULATOR
30 40 50 60 70
REQUIRED
400
NO INSULATOR NECESSARY
0
USE INSULATOR (CAUTION! IF AMBIENT DEWPOINT IS ABOVE
PROCESS TEMPERATURE ( F)
PROCESS TEMPERATURE, ICE FORMATION MAY CAUSE INSTRUMENT
MALFUNCTION AND REDUCE INSULATOR EFFECTIVENESS.)
-20 -29
0 20 40 60 80 100 120 140 160
AMBIENT TEMPERATURE (_F)
TOO
HOT
71
593
500
400
300
200
100
0
110
0
_
_
PROCESS TEMPERATURE ( C)
PROCESS TEMPERATURE ( F)
-18 -10
800
01020
HEAT INSULATOR
REQUIRED
400
NO INSULATOR NECESSARY
0
USE INSULATOR (CAUTION! IF AMBIENT DEWPOINT IS ABOVE PROCESS
TEMPERATURE, ICE FORMATION MAY CAUSE INSTRUMENT MALFUNCTION AND
REDUCE INSULATOR EFFECTIVENESS.)
-20 -29
20 40 60 80 100 120 140 200
0
NOTE: FOR SERVICE BELOW -29_C (-20_F) CONTACT FACTORY.
AMBIENT TEMPERATURE (_C)
30 40 50 60 70
AMBIENT TEMPERATURE (_F)
80 90
TOO
HOT
180160
93
593
500
400
300
200
100
0
B1413‐1
STANDARD CONTROLLER OR TRANSMITTER
HIGH‐TEMPERATURE CONTROLLER OR TRANSMITTER
Installation
2502 controllers are used in combination with 249 sensors, and unless ordered separately, the controller will be
attached to the sensor.
WARNING
Wear protective eyewear, gloves and clothing whenever possible when performing any installation operations to avoid
personal injury.
Check with your process or safety engineer for any additional measures that must be taken to protect against process
media.
If installing into an existing application, also refer to the WARNING at the beginning of the Maintenance section in this
instruction manual.
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Instruction Manual
D200126X012
2502 Controllers
June 2017
WARNING
Personal injury or property damage may result from fire or explosion if natural gas is used as the supply medium and
preventive measures are not taken. Preventive measures may include, but are not limited to, one or more of the following:
Remote venting of the unit, re‐evaluating the hazardous area classification, ensuring adequate ventilation, and the
removal of any ignition sources. For information on remote venting of this controller refer to page 12.
CAUTION
Do not use sealing tape on pneumatic connections. This instrument contains small passages that may become obstructed
by detached sealing tape. Thread sealant paste should be used to seal and lubricate pneumatic threaded connections.
249 Sensors
D 249, 249B, 249BF, 249C, 249K, and 249L sensors side‐mount on the vessel with the displacer mounted inside a cage
(caged) outside the vessel.
D 249BP and 249CP sensors top‐mount on the vessel with the displacer hanging down into the vessel (cageless).
D The 249VS sensor side‐mounts on the vessel with the displacer hanging out into the vessel (cageless).
D The 249W sensor top‐mounts on the vessel or on a customer supplied cage.
External sensors provide more stable operation than do internal sensors for vessels with internal obstructions or
considerable internal turbulence.
WARNING
When replacing the sensor assembly, the displacer may retain process liquid or pressure. Personal injury or property
damage due to sudden release of pressure, contact with hazardous liquid, fire, or explosion can be caused by puncturing,
heating, or repairing a displacer that is retaining process pressure or liquid. This danger may not be readily apparent when
disassembling the sensor or removing the displacer. Before disassembling the sensor or removing the displacer, observe
the more specific warning provided in the sensor instruction manual.
Uncrating
Unless ordered separately, the controller will be attached to the sensor when shipped. Carefully uncrate the assembly.
CAUTION
If the sensor has a thin‐walled torque tube, always support the displacer if the travel stop must be removed. A thin‐walled
torque tube has a T stamped on the sensor end flange (not visible unless the controller is removed from the sensor).
Note
Caged sensors have a rod and block installed on each end of the displacer to protect the displacer in shipping. Remove these parts
before installing the sensor to allow the displacer to function properly.
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2502 Controllers
June 2017
Instruction Manual
D200126X012
Caged sensors will be shipped with the displacer installed in the cage. If the sensor is ordered with a tubular gauge
glass, the gauge glass will be crated separately and must be installed at the site. Be certain that the cage equalizing
connections are not plugged with foreign material.
A caged sensor has a damping plate installed in the lower screwed or flanged connection to provide more stable
operation. If the process liquid could clog the plate opening with sediment, then remove the damping plate. For
screwed connections, use a 1/2‐inch hexagon wrench to unscrew the damping plate. For flanged connections, use a
screwdriver to pry the damping plate out of the flange.
A cageless sensor is shipped with the displacer separated from the sensor assembly. A displacer longer than 813 mm
(32 inches) is crated separately. A shorter displacer is crated with the sensor, but is not attached to the displacer rod.
Inspect the displacer and replace if it is dented. A dent may reduce the pressure rating of the displacer.
Controller Orientation
A controller is to be mounted with the vent opening pointing downward as shown in figure 3. This orientation is
necessary to ensure draining of accumulated moisture. The controller is attached to the sensor in one or the other of
the mounting positions shown in figure 4: Right hand (with the case to the right of the displacer when looking at the
front of the case) or left hand (with the case to the left of the displacer). The mounting position can be changed in the
field if required; refer to the appropriate sensor manual for instructions. Changing this mounting position will change
controller action from direct to reverse, or vice versa.
Figure 3. Pressure Connections
ADJUSTING
PRESSURE REGULATOR
1/4‐18 NPT
OUTPUT CONNECTION
LOCKNUT
VENT
SCREW
1/4‐18 NPT
SUPPLY CONNECTION
DRAIN VALVE
All caged sensors have a rotatable head. That is, the controller may be positioned at any of eight alternate positions
around the cage as indicated by the numbers 1 through 8 in figure 4. To rotate the head, remove the head flange bolts
and nuts and position the head as desired.
Controller‐Sensor Action
The following controller description is for right‐hand mounting. Left‐hand mounting produces an output signal with
the opposite action. Figure 4 shows cage head mounting positions.
For right‐hand mounting:
D Direct Action—Increasing liquid or interface level, or density, increases the output signal.
D Reverse Action—Decreasing liquid or interface level, or density, increases the output signal. A factory‐supplied
reverse‐acting unit has the suffix letter R added to the type number.
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Instruction Manual
D200126X012
Figure 4. Cage Head Mounting Positions
2502 Controllers
June 2017
RIGHT‐HAND MOUNTING
1 67CFR FILTER/REGULATOR.
AH9150-A
A2613-2
LEFT‐HAND MOUNTING
Mounting Caged Sensor
Note
The cage must be installed plumb so that the displacer does not touch the cage wall. Should the displacer touch the cage wall, the
unit will transmit an erroneous output signal.
Note
If the controller is not mounted on the sensor, refer to the Installing Controller on Sensor section. This section also provides
instructions for adding a heat insulator to a unit.
Cage connections will normally be either NPS 1‐1/2 or 2 screwed or flanged. Figure 5 shows the combinations. With
flanged connections, use standard gaskets or other flat‐sheet gaskets compatible with the process liquid. Spiral wound
gaskets without compression‐controlling centering rings cannot be used for flanged connections.
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2502 Controllers
June 2017
Figure 5. Cage Connection Styles
Instruction Manual
D200126X012
STYLE 1: TOP
AND BOTTOM
SCREWED: S1
FLANGED: F1
A1271-2
STYLE 2: TOP
AND LOWER SIDE
SCREWED: S2
FLANGED: F2
STYLE 3: UPPER
AND LOWER SIDE
SCREWED: S3
FLANGED: F3
STYLE 4: UPPER
SIDE AND BOTTOM
SCREWED: S4
FLANGED: F4
Mount the cage by running equalizing lines between the cage connections and the vessel (figure 6). A shutoff or hand
valve with a 1‐1/2 inch diameter or larger port should be installed in each of the equalizing lines. Also install a drain
between the cage and shutoff or hand valve whenever the bottom cage line has a liquid‐trapping low point.
On liquid or interface level applications, position the sensor so that the line marked FLOAT CENTER on the cage is
located as close as possible to the center of the liquid level or interface level range being measured. Also consider
installing a gauge glass either on the vessel, or on the sensor cage (if the cage is tapped for a gauge).
Figure 6. Caged Sensor Mounting
CENTER OF LIQUID
OR INTERFACE LEVEL
DF5379‐A
A1883‐2
8
EQUALIZING LINE
SHUTOFF
VALVES
DRAIN VALVE
EQUALIZING LINE
Instruction Manual
D200126X012
2502 Controllers
June 2017
Mounting Cageless Sensor
Note
If a stillwell is used, it must be installed plumb so that the displacer does not touch the wall of the stillwell. Should the displacer
touch the wall while the unit is in service, the unit will transmit an erroneous output signal.
Since the displacer hangs inside the vessel, provide a stillwell around the displacer if the liquid is in a state of
continuous agitation to avoid excessive turbulence around the displacer.
Note
Displacers used in an interface level application must be completely submerged during operation. If displacers aren't completely
submerged they will not calibrate or perform properly. To obtain the desired controller sensitivity may require using either a
thin‐wall torque tube, an oversized displacer, or both.
Note
If the controller is not mounted on the sensor, refer to the Installing Controller on Sensor section. This section also provides
instructions for adding a heat insulator to a unit.
Attach a cageless sensor to a flanged connection on the vessel as shown in figure 7. For interface or liquid level
applications, install a gauge glass on the vessel.
CAUTION
If the displacer is to be inserted into the vessel before being attached to the displacer rod, provide a suitable means of
supporting the displacer to prevent it from dropping into the vessel and suffering damage.
To help support a 249BP or 249CP displacer, install the displacer stem and stem end piece, or a threaded rod, into the
1/4 inch‐28 UNF threaded hole in the displacer spud or stem end piece (figure 8). On the 249BP with optional travel
stop, the stem end piece pins will secure the displacer as long as the travel stop plate is installed and the sensor head is
in position.
Side‐Mounted Sensor
If a stillwell is required (figure 7), the displacer must be attached to the displacer rod from inside the vessel. Connect
the displacer as shown in figure 8, locking the assembly with the cotter spring provided. If a stillwell is not required, the
displacer can be attached to the displacer rod before mounting the sensor to the vessel connection. The displacer may
then be swung out horizontally for insertion into the vessel. However, once the sensor is installed and the displacer
drops to a vertical position, the displacer may not be capable of being withdrawn for servicing later. Be sure there is
another access to the displacer to permit swinging it to a horizontal position or to permit disconnecting it from the
displacer rod.
9
2502 Controllers
June 2017
Figure 7. Cageless Sensor Mounting
W9517‐1
Instruction Manual
D200126X012
TOP MOUNTED
SIDE MOUNTED
SIDE VIEW (SHOWING STILLWELL)
CF5380‐A
A3893
SIDE VIEW (WITHOUT STILLWELL)
If an extension is used between the displacer spud and the displacer stem end piece, make sure the nuts are tight at
each end of the displacer stem extension. Install and tighten suitable bolting or cap screws in the flanged connection
to complete the installation.
Top‐Mounted Sensor
Figure 7 shows the installation of a top‐mounted cageless sensor. The displacer may be attached to the displacer rod
before installing the sensor on the vessel. Where the displacer diameter is small enough, it may be desirable to install a
long or sectionalized displacer through the sensor head access hole after the sensor is installed on the vessel. Connect
the displacer as shown in figure 8, locking the assembly with the cotter springs provided. If a stem is used between the
displacer as shown in figure 8, lock the assembly with the cotter springs provided. If a stem is used between the
displacer spud and the stem end piece, make sure the nuts are tight at each end of the stem. Install and tighten
suitable cap screws in the flanged connection to complete the installation.
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